Q: I have two four-year old willow oaks in my backyard. One is much fuller and its leaves look healthier than the other. I might have planted the one that looks less healthy too low in the ground? If this is the case what can I do?

A: The symptoms are certainly consistent with buried roots. Get a trowel and dig down beside the trunk to find the first roots where they flare out from the trunk. If they are more than an inch down, try gently scraping soil off the top of the root system so it can breathe. If this makes a saucer of soil that would tend to gather water around the roots, consider digging the tree next fall, raising it and planting in the same spot. If it is too deep and you don’t correct it, the sickly tree may never look good.